Oneida is a city in Madison County in the U.S. state of New York. It is located west of Oneida Castle and east of Wampsville. The population was 10,329 at the 2020 census, down from 11,390 in 2010. The city, like both Oneida County and the nearby silver and china maker, was named for the Oneida people, who had a large territory around Oneida Lake during the colonial period.